scholarly journals Modeling and Simulation of Sky Survey

2021 ◽  
Vol 11 (16) ◽  
pp. 7584
Author(s):  
Kun Hu ◽  
Hongfei Wang ◽  
Wenzhao Zhang ◽  
Yuohua Xu ◽  
Shengmao He

Sky surveys with wide and deep field are the key direction of international astronomy research for the next decades. It is worthwhile to study how to design a sky survey algorithm to obtain the maximum scientific output in a limited period of observation. In this paper, the modeling and simulation of a wide and deep sky survey mission are presented using a Staged Design Algorithm (SDA), which takes into account the inefficient time periods and difficult-to-observe sky areas. In order to ensure the effective completion of the long-time survey observation tasks in large sky areas, a two-stage scheduling algorithm is designed. Firstly, the inefficient time periods and difficult observation areas are scheduled, and then the overall observation is carried out. The prearranged schedule is arranged when inefficient time periods or difficult areas are encountered during the overall arrangement. The simulation results are verified on the basic data of the China Space Station Telescope (CSST), and the obtained simulation result is three years ahead of the target of the telescope design to complete the wide and deep sky survey of 15,000 deg2. The design ideas in this paper not only have good results for sky survey observation but also can be extended to similar satellite Earth observation mission planning.

2018 ◽  
pp. 104-106
Author(s):  
Artur Vardanyan

Cluster computing is becoming increasingly practical for high performance computing research and development. A computer cluster is a set of connected computers that work together so that, they can be viewed as a single system. Clusters offer a scalable means of linking computers together to provide an expansive environment for hosting enterprise applications. As the number of nodes in cluster configurations grows, the cluster administration becomes more challenging. We need to study the challenges of cluster management and to provide a solution. To have an effective cluster management we need to have an effective task scheduling algorithm. With the explosive growth of information, the demand on computing is sharply increasing. Due to a large number of computing tasks, the scheduling algorithm is an important part of cluster computing and has a great influence on the quality of claster service. In cluster computing, some large tasks may occupy too many resources and some small tasks may wait for a long time based on First-In-First-Out (FIFO) scheduling algorithm. This paper provides an overview of an improved scheduling algorithm that shortens the execution time of tasks and increases the resource utilization.


Author(s):  
JIANLI LIU ◽  
YIMIN YANG ◽  
SONG ZHANG ◽  
XUWEN LI ◽  
LIN YANG ◽  
...  

Electronic fetal heart rate (FHR) monitoring is a technical means to evaluate the state of the fetus in the uterus by monitoring FHR. The main purpose is to detect intrauterine hypoxia and take corresponding medical measures timely. Because the fetus sleeps quietly for up to 1 hour sometimes, ultrasound Doppler is not easy to continuously detect for a long time. The electronic fetal monitor obtains the fetal heart rate, which not only improves the accuracy and comfort, but also the convenient implementation of long-term monitoring. It is beneficial to reduce perinatal fetal morbidity and mortality. This study used maternal–fetal Holter monitor which is based on the technology of fetal electrocardiograph (FECG) to collect the FHR, and then design algorithm to extract the baseline FHR, acceleration, variation, sleep-wake cycle and nonlinear parameters. There were significant differences in the 22 parameters between the normal and the suspicious group. Using the 22 characteristic parameters, the support vector machine was used to classify the normal and the suspected group of fetuses. 80% of the data was used to train a classification model. The remaining 20% of the data was used as a test set and its accuracy reached 93.75%.


2017 ◽  
Vol 98 (5) ◽  
pp. 1097-1107 ◽  
Author(s):  
Robin E. Sarabia ◽  
Michael R. Heithaus ◽  
Jeremy J. Kiszka

Bottlenose dolphins (Tursiops truncatus) are abundant in many coastal ecosystems, including the coastal Everglades. Understanding spatial and temporal variation in their abundance and group sizes is important for estimating their potential ecological importance and predicting how environmental changes (e.g. ecosystem restoration) might impact their populations. From August 2010 to June 2012, we completed a total of 67 belt transects covering a total of 2650 linear km and an area of 1232 km2. Dolphin densities varied spatially and temporally. The highest densities of dolphins were found in coastal oceans and inland bays and were lowest in rivers. Use of rivers, however, increased during the dry season while densities in other habitats remained similar across seasons. Dolphins appeared to prefer portions of bays close to mangrove-covered islands over open waters. A resighting rate of 63.6% of individuals across the 2-year study suggests that at least a portion of the population is probably resident within study regions over long time periods. The largest groups (mean 6.28, range 1–31) were found in open waters and bays despite apparently low predation pressure. Indeed, shark bite scars – likely the result of unsuccessful predation attempts – were conclusively observed on only 1% of individuals. Although further studies are warranted, the high densities of dolphins suggest that they are an important upper trophic level predator in the coastal Everglades, but their ecological importance probably varies in space and time.


Author(s):  
Aviral Kumar Tiwari ◽  
Juncal Cunado ◽  
Rangan Gupta ◽  
Mark E. Wohar

Abstract This paper analyzes the relationship between stock returns and the inflation rates for the UK over a long time period (February 1790–February 2017) and at different frequencies, by employing a wavelet analysis. We also compare the results for the UK economy with those for the US and two developing countries (India and South Africa). Overall, our results tend to suggest that, while the relationship between stock returns and inflation rates varies across frequencies and time periods, there is no evidence of stock returns acting as an inflation hedge, irrespective of whether we look at the two developed or the two developing markets in our sample.


2019 ◽  
pp. 1-22
Author(s):  
Rachel Kahn Best

For more than a century, disease campaigns have been the causes Americans ask their neighbors to donate to and the issues that inspire them to march and volunteer. Studies of social movements, interest groups, agenda setting, and social problems tend to focus on contentious politics and study one movement or organization at a time. But these approaches cannot reveal why disease campaigns are the battles Americans can agree to fight, why some diseases attract more attention than others, and how fighting one disease at a time changes charity and public policy. Understanding the causes and effects of disease campaigns, requires studying consensus politics and collecting data on fields of organizations over long time periods.


Author(s):  
Andrew Smithers

The volume of the capital stock is defined as the original cost at constant prices of all tangible capital that has not been scrapped. Due to the poor data available for the UK my calculations and testing have had to be limited to the US. The volume of labour is defined as civilian employment. Quality improvements for both labour and capital are defined as being part of TFP. TFP is under conditions of full employment and must therefore be measured over long time periods. All growth comes from TFP, changes in labour and NTVs. The change in the volume of capital less the change in the volume of labour equals the change in NTVs and the balance is that from changes in technology (TFP). NTV is exogenous in aggregate. The value of the capital stock, but not its volume, is mean-reverting.


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